Post-harvest (the period after harvest and before leaf senescence) fertilization play an important role in the potential crop of the following season. Replacing minerals is very important as they are transported off-site in the crop. Most of these nutrients can be taken up by the crop during the post-harvest period if they are available. In many tree crops, it is one of the best times for uptake of nitrogen and potassium. Trees are still active, and the roots and foliage readily absorb applied nutrients and these nutrients become reserves for the following growing season. Autumn applications are efficient since trees are still actively taking up nutrients, cold and wet conditions in the spring can delay dormancy break, and spring-applied fertilizers could be subject to leaching and run-off.
After harvest, trees and vines are recovering from stress, so post-harvest fertilization programs accomplish several things. They can replace nutrients removed by the harvest and provides an opportunity to address nutrient deficiency issues before the next growing season. Fall applied fertilizers do not impact tree vigour so what is applied is taken up and goes into tree reserves. One key to success for early varieties and for situations where spring is late points to this technique.
In deciduous fruit trees, mineral and organic reserves have a fundamental role in the first stages of spring growth. During this period, there’s practically no transport from the roots to the aerial part, which is why spring growth is fed by a high consumption of reserve amino acids like arginine and sugars, which are contributed mostly by reserve polysaccharides, and slowly generating the contribution by photosynthesis.
The amount of time required for crops to restore their carbohydrate and mineral reserves varies by crop load and crop type. Crops with a high harvest load will need up to eight weeks to build up their reserves. Aside from NPK macronutrients, the contribution of secondary elements (calcium, magnesium and sulphur) are necessary for a larger cellular resistance and chlorophyll production without leaving aside the importance of micronutrients like iron, manganese, zinc and boron, essential for critical vital functions of trees. Without water and fertilizer at the end of the season there will be low levels of stored carbohydrates, low levels of the macronutrients and dry woody tissue. These deficiencies can lead to uneven bud break, poor and uneven shoot growth, poor set, and a higher incidence of winter injury.
When making fertilizer decisions, a combination of soil analysis, tissue analysis and crop yield history should be taken into account.
To build these reserves it is important that the chosen fertilizer will not leach, and nutrient reserves should be built as rapidly as possible. COMPO EXPERT’s Novatec® and Duratec® Technology, ensures high availability of nutrients (primary, secondary and micronutrients), lower levels of leaching and more cost-effective carbohydrate assimilation.
The COMPO EXPERT product range include all essential nutrients to ensure a balanced nutrient programme for each crop. For a fast response, to ensure nutrient levels are sufficient, a foliar fertilizer is recommended. Nutrimix® Complete and Nutribor® are foliar fertilizers with micronutrients, magnesium and nitrogen. These products can be used to ensure micronutrient levels are sufficient in plants for the start of the following season.